lecture 1 hemostasis first secion
DESCRIPTION
graphics based slides created for teaching by webzmedlecturesTRANSCRIPT
WebzmedlecturesWMLDISORDERS AFFECTING HEMOSTASIS
DEFINITION
HOW DOES THE BODY REPSOND TO THIS?
ANSWER
TECHNICALLY
• WHAT IS HEMOSTASIS: It is a complex physiological respond of the body to insult brought about by bleeding,based on the interaction of :
• Plasma factors
• Thrombocytes or platelets
• Blood vessel.
STAGES OF HEMOSTASIS
CLOTH DISSOLUTION
VESSEL SPASM
HOW DOES IT HAPPEN (SPASM OF VESSELS)
• 1. The endothelial cells send information to the smooth muscle cell and this causes their contraction.
• Information is related to the smooth to the nerve innervation of the smooth muscle
PLATELET PLUG FORMATION
ORIGINATE FROM MEGAKARYOCYTES
STEPS IN PLUG FORMATION
• PLATELETS ACTIVATION
• ADHESION OF LATELETS
• AGGREGATION OF PLATELETS.
PLATELET ACTIVATION
• Factors that activate platelets are release from their cytoplasm, and they include
• 1.ADP
• 2.Serotonin
• 3.PDGF, (platelet derived growth factor)
• Platelet factor 4
WHAT HAPPEN WHEN THEY ARE ACTIVATED?
• When platelets are activated they change their shape from a disc shape to a spherical shape
• This change of shape helps them to obtain the ability to adhere and aggregate.
ADHESION
AGGREGATION
We get the platelet plug or the primary hemostatic plug.
COAGULATION CASCADE
• Main purpose is to stabilize and strengthens the platelet plug
• To form the fibrin mesh that give that stability required.
Definition
• Coagulation cascade is a complex biological process that leads to the conversion of soluble plasma fibrinogen to fibrin.
• 3 main stages
• -formation of thromboplastine comlex
• -transformation of prothrombin to
Thrombin
.-transformation of fibrinogen to fibrin
Factors INVOLVED
THEIR INTERACTIONS
LIMITATION OF COAGULATION
• It is a good thing that this process is restricted to the particular region involve in the insult,this is achieved by inhibitors of activated coagulation factors, and fibrinolysis
FIBRINOLYTIC SYSTEM
• This process leads to the restoration of vessel potency, that is the continuity of the vessel.
HOW IT HAPPENS !!